Eco Fighters (EF) is a great-looking horizontal shooter with an interesting control scheme and a secondary weapon that is really the primary weapon.
You have two ways to shoot in EF. Your normal fire/cannon and a protruding mechanical arm that rotates 360 degrees and fires all types of upgradeable fodder. You control your ship and the weapons with a joystick and three buttons. One to fire your weapons, one to rotate your arm clockwise and one to rotate your arm counter-clockwise. This is a pretty unusual way to accomplish this. Normally, there would have been a dial/spinner or some other analog control to rotate. But this is NOT a MAME button mapping/analog replacing change, this is how the game is supposed to work. In fact, I reversed the process and programmed MAME to use the spinner to rotate the arm relative to how I moved the spinner. Remarkably, despite the fact that the spinner is analog and doesn't always work well as a replacement for a button/switch press, the game played extremely well this way also - a lot like the gameplay of previous GOTD Forgotten Worlds.
EF is a typical horz shooter for its day, albeit with superior graphics and a "save the world" theme. BUT, the arm/weapon does make the gameplay a little bit different than usual. There is so much concentration on where the arm is pointing and which weapon is being deployed that it is really your primary focus. Additionally, much of the arms weaponry is more attached to the arm then shot from it. Think flamethrower or buzzsaw. So many of your best attacks are more like direct/adjacent attacks rather than long-range missile/shot attacks. I found myself with some of the bosses just holding steady right next to them trying to fry or buzz them down like I was giving them a haircut. You can also hold down the fire button and rotate your arm resulting in a 360 spray of fire that's hard for the enemy to avoid.
I've mentioned it a couple of times, but the graphics really impress. They remind me of an Irem game - big, cartoonish, colorful and well-drawn.
There are (of course) power-ups, many of which come from increasing your power via collecting the blue gems that are omnipresent. The bottom of the screen tells you about your arm and your overall power level.
Play Eco Fighters and save the world from ecological disaster - even if you don't, you'll have fun trying.